Thermal insulation products — Exterior insulation and finish systems (EIFS) — Part 2: Installation
This document specifies requirements for the installation of exterior insulation and finish systems (EIFS) for wall applications using material which meet the materials requirements of ISO 17738‑1 and the design requirements of ISO 17738‑3. This document further includes installation requirements for the EIFS materials that include a water resistive barrier (WRB) and decorative projections as part of the cladding system for walls. This document does not include requirements for the structural design of the substrate/building structural members or for the integrity of the substrate/building structural members to which the EIFS is to be attached, nor the requirements for installation or repair of the substrate/building structural members before installation commences. This document does not include requirements for the competence that an EIFS installer needs for installation of the system. The installation of EIFS on horizontal surfaces exposed to direct precipitation is outside the scope of this document.
Produits isolants thermiques — Systèmes de finition et d'isolation externe — Partie 2: Titre manque
Standards Content (Sample)
Thermal insulation products —
Exterior insulation and finish systems
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1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 General requirements . 3
5 Materials storage and handling . 4
6 Substrate . 4
7 Mixing. 5
8 Installation of the liquid-applied water resistive barrier system . 5
8.1 General . 5
8.2 Transition membrane . 6
9 Thermal insulation boards . 6
9.1 General . 6
9.2 Attachment of the thermal insulation boards . 7
9.2.1 General. 7
9.2.2 Clearances (spacing). 8
9.2.3 Rasping and surface preparation . 8
9.3 Aesthetic reveals . 9
10 Installation of the base coat and glass fibre reinforcing mesh . 9
10.1 Attachment of the glass fibre reinforcing mesh . 9
10.2 Terminations and aesthetic reveals .12
10.2.2 Wrapped terminations.12
10.3 Base coat surface .17
11 Installation of the finish material .18
11.1 General .18
Annex A (informative) Mechanical fasteners .19
Annex B (informative) Site quality assurance programme (SQAP) .20
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This document was prepared by Technical Committee ISO/TC 163, Thermal performance and energy use
in the built environment, Subcommittee SC 3, Thermal insulation products.
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This document provides minimum installation requirements for an exterior insulation and finish
system where the materials meet the requirements of ISO 17738-1, and where the installation meets
the requirements for design in accordance with ISO 17738-3.
Exterior insulation and finish systems (EIFS) are a unique insulated cladding that consists of a water
resistive barrier system (WRB) over the substrate, a drained cavity and an insulated cladding that is
bonded adhesively to the WRB, covered with a base coat, mesh and a finish material.
A risk management process may recommend additional requirements for the establishment of a site
quality assurance programme (SQAP). Additional information related to a SQAP is included in Annex B.
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INTERNATIONAL STANDARD ISO 17738-2:2019(E)
Thermal insulation products — Exterior insulation and
finish systems (EIFS) —
This document specifies requirements for the installation of exterior insulation and finish systems
(EIFS) for wall applications using material which meet the materials requirements of ISO 17738-1 and
the design requirements of ISO 17738-3. This document further includes installation requirements for
the EIFS materials that include a water resistive barrier (WRB) and decorative projections as part of
the cladding system for walls.
This document does not include requirements for the structural design of the substrate/building
structural members or for the integrity of the substrate/building structural members to which the EIFS
is to be attached, nor the requirements for installation or repair of the substrate/building structural
members before installation commences.
This document does not include requirements for the competence that an EIFS installer needs for
installation of the system.
The installation of EIFS on horizontal surfaces exposed to direct precipitation is outside the scope of
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 7345, Thermal performance of buildings and building components — Physical quantities and definitions
ISO 4624, Paints and varnishes — Pull-off test for adhesion
ISO 8873-1, Rigid cellular plastics — Spray-applied polyurethane foam for thermal insulation — Part 1:
ISO 8873-2, Rigid cellular plastics — Spray-applied polyurethane foam for thermal insulation — Part 2:
ISO 9229, Thermal Insulation — Vocabulary
ISO 17738-1, Thermal insulation products — Exterior insulation and finish systems — Part 1: Materials
ISO 17738-3, Thermal insulation products — Exterior insulation and finish systems — Part 3: Design
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 7345, ISO 9229 and
ISO 17738-1 and the following apply.
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groove cut into the thermal insulation board for decorative purposes only
encapsulate the exposed edge of the thermal insulation board by securing a strip of glass fibre
reinforcing mesh (3.9) to the substrate and embedding it in base coat around the board edge onto the
face of the insulation
encapsulate the edge of thermal insulation board by embedding a strip of glass fibre reinforcing mesh
(3.9) in base coat and lapping it onto the face of the insulation board and onto the edge of an opening
legal entity (corporate or personal) responsible for the site installation of EIFS
insulation profile that is mounted on or incorporated into the thermal insulation boards, covered by the
lamina integrated into EIFS
joint designed to permit movement due to expansion and contraction of any part of the system
Note 1 to entry: See ISO 9229.
continuous material(s) that stops the vertical flow of water within a wall assembly or system and
directs the water, via gravity, to the exterior of the cladding
period of time that a material maintains its workable properties after it has been mixed
glass fibre reinforcing mesh
woven or non-woven glass fibre fabric material of EIFS that is encapsulated in the base coat to
encapsulate the exposed edge of the thermal insulation board with base coat and mesh, lapping onto
the front and back of the insulation board before installation
component of the WRBA (3.12) that maintains continuity of the WRB at joints and openings in the
substrate that cannot be bridged with the LA-WRB
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water resistive barrier assembly
materials possessing water resistant properties that are installed over substrates to create a continuous
drainage plane preventing water penetration into the wall assembly and draining that water to the
exterior of the wall cladding
EXAMPLE LA-WRB, transition membranes (3.11), flashing (3.7).
4 General requirements
4.1 For each project, the EIFS contractor shall obtain all the materials and components required for
the EIFS cladding from a single EIFS manufacturer.
4.2 The EIFS contractor shall incorporate the design requirements outlined in ISO 17738-3 into the
4.3 The EIFS contractor shall obtain information, in written or electronic form, from the EIFS
manufacturer, and shall keep this information at the project site:
a) Detailed description of the EIFS materials and components to be used for the specific project
b) Instructions for safe handling, use and disposal of the materials or components.
c) EIFS manufacturer’s installation instructions.
4.4 The EIFS contractor shall follow the EIFS manufacturer’s installation instructions throughout the
EIFS installation process.
4.5 Before commencing installation, the EIFS contractor shall verify that the materials and components
on site comprise the EIFS declared by the manufacturer as meeting the requirements of ISO 17738-1.
This can be accomplished by reference to a materials list or other documentation.
4.6 EIFS shall not be used at locations where the continuous service temperature exceeds +75 °C.
NOTE Service temperatures more than +75 °C can occur in proximity to chimneys, heater vents, steam pipes,
and materials of a dark colour that absorb solar radiation.
4.7 Materials and surfaces shall be protected from staining or damage by wet EIFS materials during
4.8 The installed EIFS shall be protected from water for a period required by the EIFS manufacturer.
4.9 EIFS shall be applied when:
a) the ambient temperature or surface temperature of the material is 4 °C or greater;
b) the ambient temperature or surface temperature of the material 40 °C or less.
4.10 When conditions are outside the requirements of 4.9 and protection (tenting, shading and
supplemental heat) is used, this protection shall be maintained:
a) for a minimum period of 24 h before installation,
b) during the installation of EIFS, and
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c) for a minimum period of 24 h after installation.
5 Materials storage and handling
5.1 The EIFS contractor shall verify and record that all materials delivered to the project site are in
packages, containers or bundles that are individually labelled with the EIFS manufacturer's name, product
name, product description, ISO 17738-1, country of manufacture, and lot or date code identification for
the materials and components.
5.2 Materials that are visibly damaged, frozen, in any way defective, or that are past the EIFS
manufacturer's shelf life shall not be used and shall be promptly removed from the site.
5.3 Portland cement and other dry-mix components shall be protected, kept dry, kept off the ground,
under cover (in addition to the product's packaging), and away from damp walls and surfaces.
5.4 Thermal insulation boards shall be kept in their original packaging until installed. They shall be
stacked flat, fully supported, off the ground, and under a cover designed to minimize water and ultraviolet
radiation (UV) exposure, with care taken to avoid damage to edges, ends, or surfaces.
5.5 All materials shall be protected from prolonged exposure to excessive heat or cold. Liquid materials
shall be transported and stored such that the material temperature never falls below 4 °C or exceeds 65 °C.
6.1 EIFS shall be installed on substrate consistent with the EIFS manufacturer’s allowable substrates,
as determined through ISO 17738-1 testing and specified in the contract documents.
6.2 EIFS shall be installed on a substrate that is firm, structurally sound, and undamaged. EIFS shall
not be installed on broken, cracked, rotted, decayed or delaminated substrate sheathing boards, nor on
loose, spalling or crumbing concrete or masonry unless repaired before the installation starts.
6.3 Newly constructed cast-in-place concrete and unit masonry substrates shall be allowed to cure
according to the desired strength before the installation of EIFS. Unless otherwise specified, curing time
shall be a minimum of 28 days. Repaired areas on existing (aged) walls shall cure for the 28 days, unless
the material used to repair is specifically designed to cure rapidly.
6.4 EIFS shall be installed on a substrate free of any surface contaminants that could affect the adhesion
of the EIFS, such as oil or grease, dust, form-release agents, curing compounds, paint, wax, glazing, water,
moisture, efflorescence, laitance, frost, etc. These contaminants shall be removed before commencing the
installation of EIFS.
6.5 All substrates shall be cleaned to remove loose dirt and dust using methods appropriate for the
6.6 Efflorescence and laitance on concrete, masonry, stucco, or clay tile substrates shall be removed
prior to the liquid-applied water resistive barrier (LA-WRB) installation. All loose particles and cleaner
residue shall be removed by rinsing with tap water. The surface shall be allowed to dry prior to LA-WRB
6.7 Paint on concrete or masonry surfaces shall be removed.
6.8 The EIFS shall only be installed on dry substrates with no visible moisture such as condensation,
dew, or frost.
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6.9 EIFS shall not be installed on a concrete or masonry substrate where there are unrepaired cracks
greater than 2 mm in width.
6.10 EIFS shall be installed on a substrate that is true in all directions to within 6 mm over 2 400 mm.
6.11 The substrate surface temperature shall be not less than 4 °C nor greater than 65 °C during the
installation, drying and curing of the LA-WRB, unless having demonstrated tolerance to such conditions
during ISO 17738-1 assessment.
6.12 The EIFS contractor shall visually confirm and record that the substrate is acceptable prior to
starting and throughout the installation of the LA-WRB. Installation of the LA-WRB shall not proceed if
the EIFS contractor deems the substrate unacceptable.
7.1 Clean containers, free of foreign residue and/or materials shall be used when mixing materials.
7.2 Mixing shall be done with a clean, rust-free, corrosion-resistant paddle, mixing blade or other
equipment that minimize air entrainment with a rotational speed less than 500 r/min.
7.3 Determine the quantity of dry materials mixed by weight. Record the weight of the materials of
each batch mixed on site.
7.4 Use tap water that is free from deleterious materials.
7.5 Mix factory-blended liquid materials (LA-WRB, base coat, finish coat and primers) prior to
7.6 Only additives supplied or specified by the EIFS manufacturer and tested in conformance with
ISO 17738-1 shall be used.
7.7 Mix and install materials that cure or dry within the pot-life limitations. Mixing containers shall be
kept closed when not used.
8 Installation of the liquid-applied water resistive barrier system
8.1.1 Gaps of 2 mm or less do not need to be treated. Treat gaps greater than 2 mm but not greater
than 6 mm by filling with a caulking material supplied or approved by the EIFS manufacturer. Gaps
greater than 6 mm shall have a transition membrane installed, supported by a backer rod, sealant foam
or similar material. The transition membrane shall be of sufficient width to lap both sides of a gap by a
minimum of 50 mm.
8.1.2 The LA-WRB shall be installed in two coats over the entire substrate to result in the thickness
specified. Allow the LA-WRB to dry before the installation of the second coat or installation of the thermal
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insulation board, except where the second coat of LA-WRB is being used as an adhesive to secure the
thermal insulation board.
Where the LA-WRB is returned into rough openings, the framing members should be made clean and
free from any remnant surface residues of the manufacturing or packaging process.
NOTE Where the second coat of the LA-WRB is being used as an adhesive, the above provision requires that
the first coat be allowed to dry before the second coat/adhesive is applied and the thermal insulation board
8.1.3 The EIFS contractor shall conduct a pull adhesion test in accordance with ISO 4624 to confirm
that the LA-WRB has adhered after it has cured.
8.1.4 When conditions are outside the parameters described in 4.9 and additional protection is
required for installation (4.10), the substrate temperature shall be maintained at 4°C or higher.
NOTE If the interior of the building is below 4°C then installing insulation with adhesive will keep the
substrate colder than the protected environment. Interior heating can be required to maintain substrate
8.2 Transition membrane
8.2.1 The WRBA shall be made continuous at openings, penetrations, joints in the substrate, expansion
joints, working joints, flashings, junctures to fenestration, other wall systems, and junctures with roofing
membranes by using transition membranes.
8.2.2 The WRBA shall maintain continuity at the interface with other cladding systems and/or cladding
components to prevent moisture penetration inward of the WRBA plane.
8.2.3 Where transmission membranes require primers, the primer shall be given sufficient time to
cure before installation of the transition membrane. The primer surface shall not be left exposed beyond
the time specified and the transition membranes shall be installed on the same day as priming. Primed
surfaces not covered by transition membrane on the same day shall be re-primed.
8.2.4 The transition membrane shall be rolled with a membrane roller (also called countertop roller,
laminate roller or floor roller) immediately after placement to ensure continuous adhesion.
8.2.5 Incorporate flashing into the WRBA in a ship-lapped, waterproof manner to direct water to the
exterior of the cladding.
9 Thermal insulation boards
9.1.1 The thermal insulation board shall be not less than 50 mm thick, not including the depth of a
GDDC, prior to rasping.
9.1.2 Some thermal insulation boards are required to be back-wrapped by installing base coat and
glass fibre reinforcing mesh prior to the installation of the thermal insulation boards (see 10.2.2.3).
9.1.3 The thermal insulation board shall be installed with an adhesive or LA-WRB within the maximum
time limit specified after the adhesive or LA-WRB has been installed.
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9.1.4 All terminations in the thermal insulation board shall be wrapped with base coat and glass fibre
reinforcing mesh, as described in 10.2.2.
9.1.5 EIFS mouldings projecting out from the wall’s vertical plane shall be sloped a minimum of 1:2 to
ensure that water drains from the surface, unless:
a) the EIFS moulding is protected by metal flashing or other durable material; or
b) there is an overhang above the EIFS moulding, where the vertical distance between the top of the
EIFS moulding and the underside of the overhang is not more than one quarter of the horizontal
9.1.6 EIFS at parapets shall be constructed to include structural blocking to accommodate the proper
support of flashing.
9.2 Attachment of the thermal insulation boards
184.108.40.206 Thermal insulation boards shall be installed in such a manner that the continuity of the
drainage cavity is maintained.
220.127.116.11 Thermal insulation boards shall be installed from a level base line with vertical joints staggered
by a minimum of 75 mm, as shown in Figure 1.
18.104.22.168 Thermal insulation boards shall be butted tightly together to minimize gaps between the
boards that would allow adhesive or base coat intrusion between the thermal insulation board edges.
Where gaps occur, they shall be filled as specified in 9.3.1.
22.214.171.124 Thermal insulation board joints at all inside and outside corners shall be interlocked, as shown
in Figure 1.
NOTE 1 Figure 1 is not drawn to scale. It is a schematic only to demonstrate the configuration of the thermal
NOTE 2 Board edges are interlocked at corners.
Figure 1 — Installation of thermal insulation boards
126.96.36.199 Window corners and similar re-entrant corners shall be cut out of a single thermal insulation
board in an 'L' shape. Thermal insulation boards shall not be butted together to form a re-entrant corner
at openings. Thermal insulation boards shall not be butted together at aesthetic reveals.
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188.8.131.52 Thermal insulation board joints shall be offset at least 150 mm from horizontal and vertical
substrate sheathing board joints.
184.108.40.206 Each thermal insulation board shall be installed by placing it tightly against the adjoining
thermal insulation board without lateral repositioning and minimal vertical repositioning.
220.127.116.11 Apply pressure over the entire surface of the thermal insulation board to achieve uniform
contact and an overall level surface.
18.104.22.168 Mechanical fasteners shall be used as a complement and/or as an alternate to adhesive for
attachment where the substrate does not support adhesive attachment of EIFS.
NOTE Mechanical fastening of the thermal insulation board is outside the scope of this document but can be
required for some conditions. Refer to Annex A for more information.
22.214.171.124 The thermal insulation board shall be occasionally checked for proper contact with the
substrate by removing a piece of thermal insulation board. Proper contact shall be achieved when
approximately equal portions of the adhesive remain on both the substrate and the thermal insulation
board. In cases where the adhesion has been checked, the adhesive shall be removed from the thermal
insulation board and substrate, and reapplied.
126.96.36.199 The thermal insulation board shall remain undisturbed for at least 24 h prior to proceeding
with rasping. Cool, damp weather conditions extend the time necessary for the thermal insulation board
to be bonded sufficiently that rasping will not disrupt the adhesive bond; in such situations, leave the
thermal insulation board undisturbed for a longer period.
188.8.131.52 Proprietary adhesive materials used to reduce the bond cure time shall have been tested to
demonstrate compliance with ISO 17738-1.
184.108.40.206 Architectural profiles shall be achieved using thicker thermal insulation boards or additional
layers of th